CN101456710A

CN101456710A - Prefabrication cast-in-place concrete floor

Info

Publication number: CN101456710A
Application number: CNA2007101509199A
Authority: CN
Inventors: 刘期亮
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-12-11
Filing date: 2007-12-11
Publication date: 2009-06-17

Abstract

The invention belongs to a prefabrication cast-in-situ concrete slab, which comprises the following compositions by weight portion: 290 to 360 portions of ordinary portland cement, 72 to 90 portions of fly ash, 8 to 10 portions of additive, 740 to 820 portions of sand, 900 to 1,100 portions of stones and 170 to 230 portions of water. The invention provides a prefabrication cast-in-situ concrete slab having the advantages of small shrinkage strain, strong cracking resistance and short curing time.

Description

Prefabrication cast-in-place concrete floor

Technical field

The invention belongs to the concrete technology field, especially a kind of prefabrication cast-in-place concrete floor.

Background technology

Precast concrete manufacture craft advanced person, reliable in quality, environmental pollution is little, now progressively replaces job mix concrete.Because the needs of transportation and pumping, the precast concrete utilization is added admixture and is increased concrete flowability, delays the concrete presetting period.But the agglutinate and the sand factor of precast concrete are bigger, cause the concrete shrinkage amount higher.Along with the use of high-strength concrete, high-strength cement uses more prevalent, and cement consumption also increases, and has more aggravated the increase greatly of precast concrete shrinkage.Carry out sample testing by the precast concrete shrinkage value that city's prefabrication cast-in-place concrete floor is used and recognize, the concrete shrinkage value of system of giving commonly used at present improved nearly 66% before 5 years.Fact proved that the raising of concrete shrinkage value is one of aggravation prefabrication cast-in-place concrete floor rimose important factor.Prefabrication cast-in-place concrete floor is the flexure member under other member constraint, externally under load and the internal stress effect, usually form the visible crack of different shape, investigation finds that present common distress in concrete crack is mainly caused by following reason: the crack that (1) concrete plastic shrinkage produces; (2) the thermogenetic crack of aquation of concrete hydrating reaction generation; (3) the dry crack that causes of shrinking of concrete; (4), also belong to the category of shrinkage cracking in a broad sense because the crack that outside temperature changes, the difference of temperature deformation produces between member; (5) because the crack that structural load or local stress effect cause; The inner reason of prefabrication cast-in-place concrete floor rimose is the shrinkage strain after the concrete placement, and ambient conditions is to shrink to be restricted the generation that causes inner tensile stress, when tensile stress certainly leads to the crack during greater than concrete tensile strength.The crack may produce in the concrete plasticity phase, also may produce in its sclerosis back.Contraction is concrete natural character, retrains also inevitable.In the construction too early form removal and apply construction loads and curing condition bad all be the important factor that created fractures occurs.Usually, concrete member all will be subjected to constraint in various degree, and the statically indeterminate structure that cast-in-situ floor forms acts on to external world and can produce responsive reaction.Concrete shrinkage, thermal stress, structure depression, unexpected load etc. all will cause bigger structural stress and created fractures.

Summary of the invention

The objective of the invention is to overcome the deficiencies in the prior art, provide that a kind of shrinkage strain is little, resistance to cleavage is strong.The prefabrication cast-in-place concrete floor that curing time is short.

A kind of prefabrication cast-in-place concrete floor is characterized in that: the component of this prefabrication cast-in-place concrete floor and ratio of weight and number are:

Ordinary portland cement: 290-360 parts;

72-90 parts in flyash;

8-10 parts of admixtures;

740-820 parts in sand;

900-1100 parts in stone;

170-230 parts in water.

And the intensity of described ordinary portland cement is 32.5.

And described admixture is the compound pumping agent of HX.

Advantage of the present invention and beneficial effect are:

1. this prefabrication cast-in-place concrete floor adopts flyash can reduce concrete shrinkage strain greatly as addition material, reduces the incidence of tiny crack, improves the intensity of monolithic concrete floor, even in transportation and hoisting process, also can keep globality preferably.

2. this prefabrication cast-in-place concrete floor is selected reliable in quality for use, is shunk less cement; And the coarse aggregate that grating is good, particle diameter is bigger also increases the coarse aggregate ratio; Suitably reduce sand coarse aggregate ratio, the particle diameter and the silt content of control sand ban use of fine sand; Rationally select admixture for use, select for use water-reducing rate height, dispersing property good, to the little admixture of concrete shrinkage influence, strict control water consumption has improved the intensity of concrete floor greatly.

3. a kind of shrinkage strain of the present invention is little, resistance to cleavage is strong.The prefabrication cast-in-place concrete floor that curing time is short.

Embodiment

The invention will be further described below by specific embodiment, and following examples are descriptive, is not determinate, can not limit protection scope of the present invention with this.

Embodiment 1

A kind of prefabrication cast-in-place concrete floor, wherein the component of this prefabrication cast-in-place concrete floor and ratio of weight and number are:

Ordinary portland cement: 290 parts;

72 parts in flyash;

8 parts of the compound pumping agents of HX;

740 parts in sand;

900 parts in stone;

170 parts in water.

The intensity of ordinary portland cement is 32.5.

Embodiment 2

Ordinary portland cement: 360 parts;

90 parts in flyash;

10 parts of the compound pumping agents of HX;

820 parts in sand;

1100 parts in stone;

230 parts in water.

The intensity of ordinary portland cement is 32.5.

Embodiment 3

Ordinary portland cement: 300 parts;

80 parts in flyash;

9 parts of the compound pumping agents of HX;

800 parts in sand;

960 parts in stone;

210 parts in water.

The intensity of ordinary portland cement is 32.5.

Claims

1. prefabrication cast-in-place concrete floor, it is characterized in that: the component of this prefabrication cast-in-place concrete floor and ratio of weight and number are:

Ordinary portland cement: 290-360 parts;

72-90 parts in flyash;

8-10 parts of admixtures;

740-820 parts in sand;

900-1100 parts in stone;

170-230 parts in water.

2. prefabrication cast-in-place concrete floor according to claim 1 is characterized in that: the intensity of described ordinary portland cement is 32.5.

3. prefabrication cast-in-place concrete floor according to claim 1 is characterized in that: described admixture is the compound pumping agent of HX.